/*
 * Copyright 2021 ZhongChao Blockchain Technology Research Institute.
 *
 * Copyright ConsenSys AG.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 *
 * This file has been modified by ZhongChao Blockchain Technology Research Institute to add support for Brochain.
 *
 * SPDX-License-Identifier: Apache-2.0
 */
package link.luyu.plugin.brochain.trie;

import java.util.ArrayList;
import java.util.List;
import org.apache.tuweni.bytes.Bytes;

class ProofVisitor<V> extends GetVisitor<V> implements PathNodeVisitor<V> {

    private final Node<V> rootNode;
    private final List<Node<V>> proof = new ArrayList<>();

    ProofVisitor(final Node<V> rootNode) {
        this.rootNode = rootNode;
    }

    @Override
    public Node<V> visit(final ExtensionNode<V> extensionNode, final Bytes path) {
        maybeTrackNode(extensionNode);
        return super.visit(extensionNode, path);
    }

    @Override
    public Node<V> visit(final BranchNode<V> branchNode, final Bytes path) {
        maybeTrackNode(branchNode);
        return super.visit(branchNode, path);
    }

    @Override
    public Node<V> visit(final LeafNode<V> leafNode, final Bytes path) {
        maybeTrackNode(leafNode);
        return super.visit(leafNode, path);
    }

    @Override
    public Node<V> visit(final NullNode<V> nullNode, final Bytes path) {
        return super.visit(nullNode, path);
    }

    public List<Node<V>> getProof() {
        return proof;
    }

    private void maybeTrackNode(final Node<V> node) {
        if (node.equals(rootNode) || node.isReferencedByHash()) {
            proof.add(node);
        }
    }
}
